title: The bracovirus genome of the parasitoid wasp Cotesia congregata is amplified within 13 replication units, including sequences not packaged in the particles.
abstract: The relationship between parasitoid wasps and polydnaviruses constitutes one of the few known mutualisms between viruses and eukaryotes. Viral particles are injected with the wasp eggs into parasitized larvae, and the viral genes thus introduced are used to manipulate lepidopteran host physiology. The genome packaged in the particles is composed of 35 double-stranded DNA (dsDNA) circles produced in wasp ovaries by amplification of viral sequences from proviral segments integrated in tandem arrays in the wasp genome. These segments and their flanking regions within the genome of the wasp Cotesia congregata were recently isolated, allowing extensive mapping of amplified sequences. The bracovirus DNAs packaged in the particles were found to be amplified within more than 12 replication units. Strikingly, the nudiviral cluster, the genes of which encode particle structural components, was also amplified, although not encapsidated. Amplification of bracoviral sequences was shown to involve successive head-to-head and tail-to-tail concatemers, which was not expected given the nudiviral origin of bracoviruses.
authors.affiliation: Institut de Recherche sur la Biologie de l'Insecte, UMR CNRS 7261, Faculté des Sciences et Techniques, Université F Rabelais, Tours, France.
authors.forename: Faustine
authors.initials: F
authors.lastname: Louis
authors.forename: Annie
authors.initials: A
authors.lastname: Bézier
authors.forename: Georges
authors.initials: G
authors.lastname: Periquet
authors.forename: Cristina
authors.initials: C
authors.lastname: Ferras
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Drezen
authors.forename: Catherine
authors.initials: C
authors.lastname: Dupuy
mesh_terms: D000818:Animals; D001483:Base Sequence; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics; D005260:Female; D005784:Gene Amplification; D016679:Genome, Viral; D018402:Manduca / Q000469:parasitology / Q000821:virology; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D018071:Polydnaviridae / Q000235:genetics*; D011533:Proviruses / Q000235:genetics; D012093:Replicon; D013559:Symbiosis; D014771:Virion / Q000235:genetics; D014863:Wasps / Q000472:pathogenicity* / Q000821:virology*
chemical_list: D004279:DNA, Viral